If a channel condition between an eNode B and the UE is poor, a relay node (RN) is installed between the BS and the UE such that it can provide an RF channel having superior channel conditions to the UE. In addition, a relay node (RN) is introduced to a cell edge region having a poor channel condition such that it can provide a higher-speed data channel and can extend a cell service region. As described above, the relay node (RN) has been widely used to solve the propagation shade region in a wireless communication system.
Compared to the conventional relay node (RN) art that is restricted to functions of a repeater capable of amplifying/transmitting a signal, the latest technology is being developed to cover more intelligent techniques. Furthermore, the relay node (RN) technology can reduce costs associated with increasing the number of eNode Bs and maintenance costs of a backhaul network in next generation mobile communication systems, and is requisite for extending the service coverage simultaneously while increasing the data processing rate. With the increasing development of relay node (RN) technology, the necessity for the relay node (RN) used in the conventional wireless communication system to be supported by the new wireless communication system is also increasing.
As the technology for forwarding a link connection between the eNode B and the UE is introduced to a relay node (RN) in a 3rd Generation Partnership Project Long Term Evolution-Advanced (3GPP LTE-A) system, two links having different attributes are applied to a UL carrier frequency band and a DL carrier frequency band. The connection link between the eNode B and the RN is defined as a backhaul link. Transmission of data using downlink (DL) resources according to a Frequency Division Duplexing (FDD) or Time Division Duplexing (TDD) scheme is referred to as backhaul downlink. Transmission of data using uplink (UL) resources according to the FDD or TDD scheme is referred to as backhaul uplink.
FIG. 1 is a conceptual diagram illustrating a relay backhaul link and a relay access link for use in a wireless communication system.
Referring to FIG. 1, the RN may receive information from the eNode B through a relay backhaul downlink, and may transmit information to the eNode B through a relay backhaul uplink. In addition, the relay node may transmit information to the UE through the relay access downlink, or may receive information from the UE through the relay access uplink.
Although the LTE-A system evolved from the LTE system acting as a mobile communication system supports the RN, the RN is not aware of a specific time at which the RN receives control information and data from the eNode B. As a result, the reception efficiency of a signal transmitted from the eNode B to the RN is unavoidably deteriorated.
In order to enable the LTE-A system to support the RN, a method for allocating a reference signal (RS) in a zone allocated for the RN and a method for allocating a control channel for the RN have not been investigated yet. In order to implement efficient signal transmission/reception of the RN, there are needed a method for allocating a reference signal (RS) in an RN zone and a method for allocating a control channel for the RN.